1. Field of the Invention
The present invention pertains to magnetic tape of the type employed for transducing information, and particularly to such magnetic tape having a leader for securing the magnetic tape to a reel hub.
2. Related art and Other Considerations
Manufacturers of magnetic tape cartridges (also known as magnetic tape cassettes) have historically and traditionally constructed the tape portion of the cartridge in the manner illustrated in FIG. 1. In particular, a small piece of adhesive-coated tape 20 (sometimes referred to as a xe2x80x9csplicing tapexe2x80x9d or xe2x80x9csplice tapexe2x80x9d) has been used in a lap joint configuration to join magnetic tape 22 to a leader 24. The leader 24 attaches to a reel hub 26 around which the tape is to be wound.
In the prior art, the length K of the splicing tape 20 is short compared to the circumference of the reel hub 26. Unfortunately, the presence of a shorter-than-circumference splicing tape creates xe2x80x9cbumpsxe2x80x9d B or xe2x80x9cprint-throughsxe2x80x9d in the tape pack as shown in FIG. 2. As additional tape layers are wound on hub 26, the inward pressure increases on the inner layers, and the stress in the magnetic tape 22 at the discontinuities attributable to the splicing tape-created bumps B at the angular positions indicated by arrows 32. The stress may be high enough to create permanent deformations in the magnetic recording tape. These deformations appear as two vertical folds in the magnetic tape. The deformations remain (and can even become permanent) after the magnetic tape has been unwound from the reel hub, as illustrated by deformations 34 in FIG. 3. The permanent deformations are greatest in the first outer tape layer adjacent to the splicing tape, and can persist for many layers.
The deformations occasioned by the prior art splicing tape create an undesired signal losses when a transducing head attempts to record or reproduce information with respect to the magnetic tape. The signal losses are attributable, at least in part, to the increased head-to-tape spacing with both helical and longitudinal recording methods. Areas of the magnetic tape having the permanent deformations may be rendered unusable.
What is needed, therefore, and an object of the present invention, is a way to minimize or counteract the deformations occasioned by a splicing tape which joins magnetic recording tape to a leader or trailer.
A pack of magnetic recording tape comprises a splicing tape which adheres a web of magnetic tape to a leader. The leader attaches to a reel hub around which the tape is to be wound. The length L of the splicing tape in a direction parallel to an elongate dimension of the magnetic tape is on the order of Nxcfx80D, where D is the diameter of the reel hub and N is an integer. In one embodiment, the length L of the splicing tape is just slightly less than the circumference of the reel hub.
The present invention provides a tape assembly having a combination of magnetic tape, a leader, and a splicing tape that greatly reduces the amount of permanent tape deformation, and provides a more efficient tape pack with smaller discontinuities. Consequentially, the stress on the magnetic tape is greatly reduced, which reduces the amount of permanent deformation and the number of magnetic tape layers that are affected by the deformations. This minimizes the area of the magnetic tape that may be rendered unusable.
The tape pack of the present invention can be utilized in a magnetic tape cassette or cartridge. The cassette or cartridge can be of a type which has both a supply reel hub and a take-up reel hub, and between which the magnetic tape extends. The splicing tape of the present invention can be utilized to secure the magnetic tape to a leader at the supply reel hub, or to a leader at the take-up reel hub, or both. Alternatively, the cassette or cartridge with which the tape pack of the present invention is operable can be a single reel cartridge.